Determine dough rheological properties during sheeting operations.

Dough sheeting is an important unit operation in the manufacture of noodles, pasta and other food products. The material properties of the dough during the sheeting process significantly impact the quality of the final product. Several investigators have proposed harnessing operational parameters during the sheeting operation, notably power consumption, to determine the dough rheological properties online.

Scientists at Purdue University wanted to determine if the rheological property of dough can be characterized online by measuring power consumption during sheeting operations. They used a laboratory sheeter to test dough made from all-purpose, bread and durum flours. Bread flour is a high-gluten flour that has very small amounts of malted barley flour and vitamin C or potassium bromate added to it. All-purpose flour is made from a blend of high- and low-gluten wheats, and has a bit less protein than bread flour--11% or 12% compared with 13% or 14%. Semolina is the endosperm or heart of the durum wheat kernel, a hard wheat variety with very high gluten content and a high protein-to-carbohydrate ratio. Durum wheat is more coarsely ground than other flours. The milling process separates the endosperm from the rest of the grain. Durum flour is finely ground semolina (endosperm).

The dough was sheeted at various height and roller gaps. Researchers measured the power consumption of the sheet motor in order to characterize dough rheological properties. They used a mathematical model based on the motor's lubrication approximation.

To validate the results, the rheological properties of these materials were measured offline using a capillary viscometer. The online rheological measurement from the sheeting operation was in very good agreement with the offline capillary rheometry for the all-purpose, bread and durum flours.

The results indicate that online rheological characterization can be performed by measuring such operational parameters as sheeting power. The power law model is appropriate to use to describe the rheology of dough in order to characterize its rheology online. These findings can be harnessed for online quality control of dough during sheeting operations. There may be some opportunities to continue this work in cooperation with a cereal company.

Further information. Osvaldo Campanella, Department of Agricultural and Biological Engineering, FS-2151, Purdue University, 225 South University St., West Lafayette, IN 47907; phone: 765-496-6330; fax: 765-496-1115; email: campa@purdue.edu.